This study determined the association between Myf5, CAST and MSTN genes and fattening
performance traits in 228 (Holstein ¼ 103 and Brown ¼ 125) cattle breeds. Classification
and regression tree (CART) was used to determine association between genes and fattening
performance. The allele frequencies of Holstein cattle in terms of Myf5, CAST and MSTN
genes were A:0.30, B:0.70; A:0.43, G:0.56; A:0.97, B:0.03, respectively, whereas in the Brown
Swiss cattle were A:0.36, B:0.64; A:0.65, G:0.34; A:0.88, B:0.12 respectively. The Myf5, CAST,
and MSTN genes were found to be in the Hardy–Weinberg equilibrium (p > 0.05) in both of
the cattle breeds. As a result, the association between Myf5, CAST and MSTN genes and fattening performance traits were found to be significant according to CART analysis.